When Mayor Thomas M. Menino took office in 1993, Boston’s downtown was in the grip of a recession. Construction had slowed to a crawl, retailers were struggling, and the elevated Central Artery still spewed exhaust onto a waterfront that was more gritty than glitzy.

Then, an improbable chain of events unfolded: The Big Dig, massive cost overruns and all, replaced the rusting steel of the artery with a series of parks; people and new stores began moving back into the city’s core; and developers created bold plans for North Station, Downtown Crossing, and the South Boston waterfront.

Today, those sparks of renewal are exploding in a historic spate of development, with more than 5,700 homes under construction and huge office, retail, and housing complexes rising from the South Boston Innovation District to Dudley Square. While he was not directly responsible for all of those projects, Menino played a central role in rebuilding a city that is now among the world’s top markets for real estate investment.

“So much of Boston has been reborn,” said Greg Vasil, chief executive of the Greater Boston Real Estate Board. “It’s remarkably different in terms of the kind of development we have now. Just the feel of the city is different.”

Menino, a longtime city councilor who was elected mayor as a champion of the city’s neighborhoods, has had a profound impact on downtown construction.

Over the last six months of his tenure, the Boston Redevelopment Authority approved a series of massive developments that will ensure that the mayor’s legacy, for better or worse, will be visible for years to come. The projects include a towering, multibuilding redevelopment of the Government Center Garage, a cluster of massive buildings in front of the TD Garden, and a new skyscraper at the edge of the Christian Science Plaza.

Taken together, the developments reflect both the city’s extraordinary growth in the Menino era and the challenges such growth creates. All three projects include luxury housing and hotel rooms that are already plentiful in a downtown fast becoming an exclusive province of the wealthy. While the developments have been greeted enthusiastically by many, critics say developers and the BRA have not paid enough attention to concerns about traffic and the pedestrian environment, as well as the wind and shadows created by tall buildings.

“At what cost does the mayor finish his administration by trying to push through projects in late night hearings that will be here for decades and decades past his time?” said Lisa Pedicini, who owns a condo next to the site of another luxury hotel and residential tower recently approved in the Back Bay.

Throughout his tenure, Menino also attracted criticism for supporting the projects of a select group of developers and contractors. Meanwhile, the projects of the less favored either languished or died in a morass of city-imposed red tape.

Menino has grown accustomed to criticisms of the city’s development review process but doesn’t accept them. In a recent interview, he noted that the building proposals were subjected to months of community meetings and government review. He said the ultimate decisions were guided by the best interests of the city as a whole, not individual developers or groups.

“We’ve never pushed anything through the BRA that the community hasn’t wanted,” Menino said. “There may be a couple of people against a [given project], but 99 percent of the people want it. People are always involved in our process. How much more process can you have? You can process things to death sometimes and not get anything done.”

While the wisdom of individual developments can be debated, the scope of change that has transformed swaths of Boston in the last 20 years is undeniable.

In 1993, broad stretches of the city were in decay. The Combat Zone still marred downtown with seedy strip bars and nightclubs, while the Central Artery and elevated Green Line tracks cast shadows on parts of the city that seemed frozen in the 1950s.

Over the next decade, the Big Dig created new highway and transit connections to North Station and the Seaport District, laying the groundwork for billions of dollars in private real estate investment. The Institute of Contemporary Art’s striking new building opened at the water’s edge in late 2006, and cultural institutions across the city, including the Isabella Stewart Gardner Museum and the Museum of Fine Arts, undertook grand expansions.

“When I came into office, a lot of economists told me, ‘Mayor, you’re going to preside over a wake — nothing is going to happen in the city,’ ” Menino recalled. “And look what happened. They were wrong. I took a lot of hits because I supported the Big Dig. I had a sense that it was going to be good for Boston, and it’s been good for Boston.”

Not all of the mayor’s efforts were successful. Plans to move City Hall to the Seaport District collapsed, as did efforts to build a signature, 1,000-foot tower above a decaying city-owned parking garage in the financial district. Several ambitious projects by private developers died or went nowhere, including major air rights developments over the Massachusetts Turnpike at Columbus Center and another one that is now stalled in the shadows of Fenway Park.

But the Seaport, renamed the Innovation District by Menino, is experiencing a major growth spurt after years of fits and starts. The area’s endless sea of parking lots is now bustling with construction activity. New office and residential towers are rising at Fan Pier and Pier 4, and the crowds of daily commuters are so large that they clog bridges and tunnels built to help spur the district’s growth.

Commercial real estate executive Kevin Phelan acknowledged the pace of building in the Seaport is remarkable, but he said the most notable change of the past 20 years is that large-scale redevelopment is now spreading to outlying sections of Boston.

Elkus Manfredi Architects

Sports apparel giant New Balance plans to build a 14-acre campus in Brighton that will include a new sports complex, retail stores, a commuter rail station and additional offices.

For example, he said, a huge complex is under construction at New Balance’s headquarters in Brighton, where contractors are building new offices, a sprawling sports complex, and retail stores. In Dudley Square, the city’s investment in new school department offices, along with a police station and public library, has begun to spark development of new homes, offices, and retail stores.

“The tax base and the jobs that will result from stretching the city in that way will be a huge legacy for Menino,” said Phelan, cochairman of the commercial real estate firm Colliers International. “That development will wake people up to the possibilities of places like Melnea Cass in Roxbury and Rutherford Ave. in Charlestown.”

But the improvements made during two decades are hardly the work of one man. In addition to federal and state transportation improvements, Boston’s economy has thrived through the growth of its hospitals and universities. Over the last 15 years, medical institutions have built more than 3.3 million square feet of new space for patient care and research, creating more than 6,300 new jobs, according to BRA data.

New pharmaceutical companies and technology firms also have moved into the city, attracting the attention of real estate investors from around the world. Every commercial building that goes up for sale in the downtown area draws a long list of would-be buyers, including insurance companies, pension funds, and multinational investment firms.

“Buildings are selling for two and three times what they did in the 1990s,” said Phelan. “If they were going for $250 to $300 a square foot back then, they are going for $600 to $800 a square foot now. People want to be here.”

Still, for investors and residents, navigating the city’s review process can be maddening. Despite its size and attractiveness, Boston still has no clear zoning rules governing development, which effectively means the mayor has the power to decide what gets built where and by whom.

Menino said he has no regrets about the projects he has supported, noting that Boston, for all the concerns about the side-effects development, has added 20,000 housing units between 2000 and 2010, and now has more than $6 billion in projects under construction.

“Some people want Boston to stay as it was 20 or 30 years ago,” he said. “Well, if you stay with the status quo, it means your city is going backwards. You’ve got to have change to make sure it’s moving forward. And that’s what we’ve tried to do, move the city forward.”